Such a steering column arrangement is discussed in German patent document DE 33 28 283 A1, for example.
The state of the art further discusses a number of safety steering columns, which in the event of an accident are intended to protect the driver of a motor vehicle from injuries caused by the steering wheel or the steering column. German patent document DE 195 22 389 C1, for example, discusses a safety steering column having a set bending point, which is capable of bending in the event of an accident in such a way that the steering column and the steering wheel do not come any nearer to the driver, even if vehicle body parts situated in front of the driver are displaced towards the driver.
German patent document DE 27 51 068 C2 also discusses a similar device, the steering wheel in this case being additionally connected to the steering column by deformable spokes, which in an accident are deformed in such a way that the plane of the steering wheel is aligned parallel to the plane of the driver's thorax.
Modern vehicles do not have steering wheels with such spokes, however, the steering wheels generally having a more extensive hub cap, often also accommodating an airbag. In contrast to automobiles the steering wheel in motor trucks is generally arranged relatively horizontally, that is to say a plane defined by the steering wheel extends at a relatively small angle to the plane of the roadway, whereas in automobiles this angle is substantially larger. As a result, in the event of an accident the lower area of the steering wheel, which is situated closer to the driver than the upper area of the steering wheel, collides with the upper abdomen or the thorax of the driver and due to its small area poses a considerable risk of injury.
In systems known through prior public use (the firms Scania and IVECO, for example) the steering column is capable of pivoting via a joint and in the event of an accident can therefore be pushed forwards in the direction of travel by the driver. Since the pivot joint is situated below the steering wheel, this pivoting causes the steering wheel to become even more horizontally aligned, thereby reducing the aforementioned angle still further and increasing the risk of injury. Reference is made to FIGS. 7 and 8 for explanation of this state of the art.
FIG. 7 shows a first steering column arrangement having a steering column 1, which is attached by a pivot joint 2 to a pedal unit 3 of the vehicle. A steering wheel 4, which in the normal driving position is inclined at an angle α, is attached to the steering column 1. The steering column 1 is connected to the body of the vehicle by a damping element 5. In the event of an accident the driver with his upper body will first come into contact with the underside 6 of the steering wheel 4, thereby generating a force which is represented by an arrow 7. In the pivot joint 2 this force generates a torque which is represented by an arrow 8. The steering column 1 together with the steering wheel 4 can thereupon pivot into the position represented by dashed lines, deforming the damping element 5. It can be seen that the angle α is thereby reduced, which increases the surface unit pressure of the steering wheel against the driver and hence the risk of injury.
A similar system according is shown in FIG. 8. There the pivot bearing 2 is located closer to the steering wheel 4 and designed so that if a force threshold is exceeded it will allow pivoting, for example through a frictional connection in the pivot joint 2, although here too the angle α is reduced due to the pivoting.
It may be understood from the state of the art discussed as to FIGS. 7 and 8 that in the event of tensile forces, that is to say forces counter to the direction of the arrow 7, no pivoting is possible.